BRPI0811421B1 - INHIBITION OF CORROSION BY NAFTENIC ACID USING A NEW SYNERGISTIC COMBINATION OF PHOSPHORUS COMPOUNDS - Google Patents

Abstract

inhibition of naphthenic acid corrosion using a new synergistic combination of phosphorus compounds. The present invention relates to the hydrocarbon processing field which causes corrosion on the metal surfaces of the processing units. The invention addresses the technical problem of high temperature naphthenic acid corrosion and sulfur corrosion and provides a solution to inhibit these types of corrosion. The 3 combined compositions are formed of 3 mixtures separately, with a mixture obtained by mixing compound a, which is obtained by reacting highly reactive polyisobutylene (hrpib) with phosphorus pentasulfide in the presence of a catalytic amount of sulfur with compound b. such as trialkyl phosphate and the second mixture obtained by mixing compound a with compound b such as diisodecyl phenyl phosphite type phosphite, and the third mixture obtained by mixing compound a with compound d such as phosphonate, where each of these 3 mixtures independently provides high corrosion inhibition efficiency in case of high temperature naphthenic acid corrosion and sulfur corrosion. The invention is useful in all hydrocarbon processing units such as refineries, distillation columns and other petrochemical sectors.

Description

INHIBITION OF CORROSION BY NAFTENIC ACID USING A NEW SYNERGIC COMBINATION OF PHOSPHORUS COMPOUNDS

Field of the Invention (001) The present invention relates to inhibiting metal corrosion in high temperature acidic hydrocarbons and more particularly to inhibiting corrosion of metals containing iron in high temperature acidic hydrocarbons, especially when acidity originates from presence of naphthenic acid. The invention is also useful for inhibiting sulfur corrosion. Discussion of the Prior Art (002) It is widely known in the art that the processing of crude oil and its various fractions causes damage to the piping and other associated equipment due to corrosion by naphthenic acid. This is corrosive to the equipment used to distill, extract, transport and process crude oil. Generally speaking, naphthenic acid corrosion occurs when the crude oil being processed has a neutralization value or total acidity index (TAN), expressed as the milligrams of potassium hydroxide needed to neutralize the acids in a sample of one gram, above 0.2. It is also known that the hydrocarbon containing naphthenic acid is found at a temperature between about 200 ° C and 400 ° C (approximately 400 ° F-750 ° F) and also when fluid speeds are high or the liquid marks the surfaces of the process, eg transfer lines, return curves and restricted flow areas.

(003) Corrosion problems in oil refining operations associated with the components of naphthenic acid and sulfur compounds in crude oils have been recognized for several years. Such corrosion is particularly serious

Petition 870170084741, of 11/03/2017, p. 17/60

2/41 in atmospheric and vacuum distillation units at temperatures between 400 ° F and 790 ° F. Other factors that contribute to the corrosivity of crude oils containing naphthenic acids include the amount of naphthenic acid present, the concentration of sulfur compounds, the speed and turbulence of the flow in the units and the location in the unit (eg, liquid interface /steam).

(004) As commonly used, "naphthenic acid" is a collective term for certain organic acids present in various crude oils. Although there may be small volumes of other organic acids, it is understood that most acids in crude oils based on naphthenic acid are naphthenic in character, that is, with a saturated ring structure as follows:

• molecular weight of naphthenic acid can vary widely. However, most naphthenic acid from crude oils is found in gasoline and light lubricating oil. When hydrocarbons containing this naphthenic acid come into contact with metals that contain iron, especially at elevated temperatures, serious corrosion problems arise.

(005) Naphthenic acid corrosion has been a problem for the refinement industry for several years. This corrosive material consists predominantly of monocyclic or bicyclic carboxylic acids with a boiling range between

350 ° and 650 ° F. These acids tend to be concentrated in the heaviest fractions during the distillation of crude oil. Thus, places such as furnace piping, transfer lines, fractionation towers interiors, feeding and reflux sections of columns, heat exchangers, tray bottoms and condensers

Petition 870170084741, of 11/03/2017, p. 18/60

3/41 are primary points of attack for naphthenic acid. In addition, when stocks of crude oil with a high content of naphthenic acid are processed, severe corrosion can occur in the ferritic or carbon steel tubes of the furnace and at the bottom of the towers. Recently, there has been an increase in interest in controlling this type of corrosion in hydrocarbon processing units due to the presence of naphthenic acid in crude oil in places like China, India, Africa and Europe.

(006) Crude oils are mixtures of hydrocarbons that have a range of molecular structures and a consequent range of physical properties. The physical properties of naphthenic acids that may be contained in hydrocarbon mixtures also vary with changes in molecular weight, as well as with the oil source that contains the acid. Therefore, the characterization and behavior of these acids are not well understood. A well-known method used to "qualify" the acid concentration in the crude oil is titration of the oil with KOH. The oil is titrated with KOH, a strong base, to an end point that ensures that all acids in the sample have been neutralized. The unit of this titration is the mg of KOH / gram of the sample and is called the “Total Acidity Index” (TAN) or Neutralization Index. Both terms are used interchangeably in the application.

(007) The TAN unit is commonly used because it is not possible to calculate the acidity of the oil in terms of moles of acid, or any other of the usual analytical terms for the acid content. Refineries use TAN as a general guideline to predict corrosion by naphthenic acid. For example, many refineries mix their crude oil up to a TAN = 0.5 assuming that in these

Petition 870170084741, of 11/03/2017, p. 19/60

4/41 concentrations will not cause corrosion by naphthenic acid. However, this measure has been unsuccessful in preventing corrosion by naphthenic acid.

(008) The corrosion by naphthenic acid depends a lot on the temperature. The generally accepted temperature range for this corrosion is between 205 ° C and 400 ° C (400 ° F and 750 ° F). A corrosion attack by these acids below 205 ° C has not yet been reported in the published literature. As for the upper limit, the data suggest that corrosion rates peak at about 600 ° -700 ° F and then start to decrease.

(009) The concentration and speed of the acid / oil mixture are also important factors that influence naphthenic acid corrosion. This is evidenced by the appearance of the surfaces affected by naphthenic acid corrosion. The corrosion mode can be deduced from the patterns and chromatic variations on the corroded surfaces. Under some conditions, the metal surface is thinned evenly. Thinning areas also occur when condensed acid runs down the wall of a container. Alternatively, in the presence of naphthenic acid, punctiform corrosion occurs frequently in plumbing or welding. Generally the metal outside the pit is covered with a heavy, black sulphide film, while the surface of the pit is shiny metal or has a thin film between gray and black covering it. In addition, another pattern of corrosion is erosion-corrosion, which has a characteristic pattern of gouges with sharp edges. The surface appears clean, with no visible by-products. The corrosion pattern of the metal is indicative of the flow of fluids within the system, since greater contact with surfaces allows a greater amount of corrosion to occur. Therefore, the corrosion standards provide information as to the type of corrosion that has occurred. Furthermore, the more complex the corrosion, that is, in

Petition 870170084741, of 11/03/2017, p. 20/60

5/41 increasing complexity of uniform for point corrosion for corrosion erosion, lower is the TAN that triggers the behavior.

(0010) The information provided by the corrosion standards indicates whether naphthenic acid is the corrosive agent or whether the corrosion process occurs as a result of the sulfur attack. Most crude oils contain hydrogen sulfide and therefore immediately form iron sulfide films on carbon steel. In all cases that were observed in the laboratory or in the field, the metal surfaces were covered with a film of some kind. In the presence of hydrogen sulfide, the film formed is invariably iron sulfide, while in some cases where tests were carried out under sulfur-free conditions, the metal is covered with iron oxide, as there is always enough water or oxygen present to produce a thin film over the metal test samples.

(0011) The tests used to determine the extent of corrosion can also serve as indicators of the type of corrosion occurring within a specific hydrocarbon treatment unit. Metal test samples can be inserted into the system. As they are corroded, they lose matter. This weight loss is recorded in units of mg / cm.sup.2. From there, the corrosion rate can be determined from the weight loss measurements. Then the ratio of the corrosion index to the corrosion product (mpy / mg / cm.sup2) is calculated. This is another indication of the type of corrosion process that occurs, because if this ratio is less than 10, it appears that there is little or no contribution of naphthenic acid to the corrosion process. However, if the ratio exceeds 10, then naphthenic acid is a significant contributor to the corrosion process.

Petition 870170084741, of 11/03/2017, p. 21/60

6/41 (0012) Distinguishing between sulphide attack and corrosion caused by naphthenic acid is important, since different solutions are necessary depending on the corrosive agent. Generally, the delay in corrosion caused by sulfur compounds at elevated temperatures is achieved by increasing the amount of chromium in the alloy that is used in the hydrocarbon treatment unit. A range of alloys can be employed, from 1.25% Cr to 12% Cr, or perhaps even more. Unfortunately, these show little to no resistance to naphthenic acid. To compensate for the corrosive effects of sulfur and naphthenic acid, an austenitic stainless steel containing at least 2.5% molybdenum must be used. It is known that the corrosive problem is aggravated by the high temperatures necessary to refine and crack the oil and by the acidity of the oil that is caused primarily by the high levels of naphthenic acid inherent in crude oils. Naphthenic acids are corrosive in the range between about 175 ° C and 420 ° C. At higher temperatures, naphthenic acids are in the vapor phase and under lower temperatures the corrosion rate is not severe. The corrosiveness of naphthenic acids appears to be exceptionally severe in the presence of sulfide compounds, such as hydrogen sulfide, mercaptans, elemental sulfur, sulfides, disulfides, polysulfides and thiophenols. Corrosion due to sulfur compounds becomes significant at temperatures up to 450 ° F. The catalytic generation of hydrogen sulfide by the thermal decomposition of mercaptans has been identified as the cause of sulfidic corrosion.

(0013) Sulfur in crude oils, which produces hydrogen sulfide under high temperatures, also exacerbates the problem. The temperature range of main

Petition 870170084741, of 11/03/2017, p. 22/60

7/41 interest for this type of corrosion is in the range of about 175 ° C to about 400 ° C, especially about 205 ° C to about 400 ° C.

(0014) Various approaches to naphthenic acid corrosion control include neutralizing and / or removing naphthenic acids from the crude oil being processed, mixing oils with a low acidity index with corrosive oils with a high acidity index to reduce the index of total neutralization, and the use of relatively expensive corrosion-resistant alloys in the construction of pipes and associated equipment. These attempts are generally disadvantageous in that they require additional processing and / or add substantial costs to the treatment of crude oil. Alternatively, various amine or amide-based corrosion inhibitors are commercially available, but are generally ineffective in the high temperature environment of naphthenic acid corrosion. Corrosion by naphthenic acid is readily distinguishable from conventional fouling problems such as coke formation and polymer deposition that can occur in cracking ethylene and other hydrocarbon processing reactions using petroleum-based raw materials. The corrosion by naphthenic acid produces characteristic indentations in the metal in contact with the corrosive flux. In contrast, coke deposits generally have corrosive effects due to carburization, erosion and spraying of the metal.

(0015) Since these approaches have not been entirely satisfactory, the accepted approach in the sector is the construction of the distillation unit, or parts exposed to corrosion by naphthenic acid / sulfur, with resistant metals such as high quality stainless steel or alloys containing higher amounts of chromium and molybdenum. The installation of corrosion resistant alloys is expensive, since alloys such as stainless steel 304 and 316 are several times the cost of carbon steel. Yet,

Petition 870170084741, of 11/03/2017, p. 23/60

8/41 in units that are not built like this, there is a need to provide an inhibition treatment against this type of corrosion. Prior art corrosion inhibitors for naphthenic acid environments include nitrogen based film corrosion inhibitors.

(0016) However, these corrosion inhibitors are relatively ineffective in the high temperature environment of oils with naphthenic acid.

(0017) Although various corrosion inhibitors are known in various arts, the effectiveness and usefulness of any specific corrosion inhibitor depends on the particular circumstances in which it is applied. Thus, effectiveness or utility under one set of circumstances often does not imply the same for another set of circumstances. As a result, a large number of corrosion inhibitors have been developed and are in use for application in various systems depending on the treated medium, the type of surface that is susceptible to corrosion, the type of corrosion encountered and the conditions to which the medium is exposed . For example, U.S. Patent Number 3,909,447 describes certain corrosion inhibitors as useful against corrosion in relatively low temperature oxygenated aqueous systems such as flooded areas, cooling towers, cooling sludge, compressed air and radiator drilling systems. automobiles. This patent also notes that many corrosion inhibitors capable of acting in non-aqueous systems and / or non-oxygenated systems act poorly in oxygenated and / or aqueous systems. The opposite is also true. The mere fact that an inhibitor shows efficacy in aqueous oxygenated systems does not suggest that it would show efficacy in a hydrocarbon. Furthermore, the mere fact that an inhibitor has been effective at relatively low temperatures does not indicate that it would be effective at elevated temperatures. In fact, it is common for inhibitors that are quite

Petition 870170084741, of 11/03/2017, p. 24/60

9/41 effective at relatively low temperatures become ineffective at temperatures like the 175 ° C to 400 ° C found in oil refinement. At such temperatures, corrosion is notoriously problematic and difficult to alleviate. Thus, U.S. Patent No. 3,909,447 contains no teaching or suggestion that would be effective in non-aqueous systems such as hydrocarbon fluids, especially hot hydrocarbon fluids. Nor is there any indication in U.S. Patent No. 3,909, 447 that the compounds disclosed therein would be effective against naphthenic acid corrosion under such conditions.

(0018) Vacuum and atmospheric distillation systems are subject to corrosion by naphthenic acid when processing certain crude oils. The treatments currently used are thermally reactive under the temperatures of use. In the case of phosphorus-based inhibitors, it is believed that this causes a superficial film of phosphate in the metal. The film is more resistant to corrosion by naphthenic acid than basic steel. These inhibitors are relatively volatile and exhibit reasonably narrow distillation ranges. They are fed to a column above or below the corrosion point depending on the temperature range. Polysulfide inhibitors break down into complex mixtures with a greater or lesser content of polysulfides and, perhaps, elemental sulfur and mercaptans. Thus, the volatility and protection offered are not predictable.

(0019) The problems caused by corrosion by naphthenic acid in refineries and the prior art solutions to this problem have been extensively described in the literature, the following being representative:

(0020) US patent number 3,531,394 to Koszman described the use of phosphorus and / or bismuth compounds in the cracking zone of furnaces

Petition 870170084741, of 11/03/2017, p. 25/60

10/41 oil to inhibit the formation of cokes on the walls of the furnace tubes.

(0021) US patent number 3,531,394 to Koszman described the use of phosphorus and / or bismuth compounds in the cracking zone of oil furnaces to inhibit the formation of cokes on the walls of the furnace tubes.

(0022) US patent number 4,024,049 to Shell et al. discloses compounds substantially as described and claimed herein for use as anti-polymerizing agents (antifoulants) for refineries. Although effective as antipolymerizing materials, materials of this type have not so far been used as corrosion inhibitors in the manner presented here. Although this reference teaches the addition of thiophosphate esters such as those used in the invention to the incoming feed, due to the non-volatile nature of the ester materials, they are not distilled back to protect the column, the pumping pipeline or other stages of the process. process. I found that by injecting thiophosphate esters as taught here, an amazing activity is obtained in preventing the occurrence of naphthenic acid corrosion in distillation columns, pumping plumbing and associated equipment.

(0023) US patent number 4,105,540 to Weinland describes phosphorus-containing compounds as antipolymerizing additives in ethylene cracking furnaces. The phosphoric compounds used are composed of mono and diester phosphate and phosphite with at least a portion of hydrogen forming a complex with an amine.

(0024) US patent number 4,443,609 discloses that certain esters and phosphonic acids of tetrahydrothiazole are useful as inhibitors of acid corrosion.

Petition 870170084741, of 11/03/2017, p. 26/60

11/41

Such inhibitors can be prepared by reacting certain 2,5-dihydrothiazoles with a dialkyl phosphite. Although these esters or phosphonic acids of tetrahydrothiazole have good corrosion and inhibiting properties, they tend to decompose during application under high temperature, with possible emission of unpleasant and toxic substances.

(0025) Phosphorus-containing compounds are also known to impair the function of various catalysts used to treat crude oil, eg in fixed bed hydrotreating reactors and hydrocracking units. Crude oil processors are often faced with a dilemma as if the phosphite stabilizer is not used, iron can accumulate in the hydrocarbon up to 10 to 20 ppm and compromise the catalyst. Although non-phosphoric inhibitors are commercially available, they are generally less effective than phosphorus-containing compounds.

(0026) American patent number 4,542,253 to Kaplan et al. described an improved method to reduce scale and corrosion in ethylene cracking furnaces using petroleum feedstock including at least 10 ppm of water-soluble amine in a complex with phosphate ester, phosphite, thiophosphate or thiophosphite compound, where the amine has a partition coefficient above 1.0 (equal solubility in both aqueous and hydrocarbon solvents).

(0027) American patent number 4,842,716 to Kaplan et al. describes an improved method for reducing scale and corrosion with at least 10 ppm of a combination of a phosphoric antipolymerizing compound and a film inhibitor. The phosphoric compound is a phosphate ester, phosphite, thiophosphate or thiophosphite compound. The film inhibitor is an imidazoline compound.

Petition 870170084741, of 11/03/2017, p. 27/60

12/41 (0028) American patent number 4,941,994 to Zetmeisl et al. discloses a naphthenic acid corrosion inhibitor consisting of a dialkyl or trialkylphosphite in combination with an optional thiazoline.

(0029) A significant advance in naphthenic acid corrosion inhibitors has been reported in U.S. Patent No. 4,941,994. It is revealed that corrosion of the metal in high temperature acidic liquid hydrocarbons is inhibited by the presence of a volume of dialkyl and / or trialkylphosphite that inhibits corrosion with an optional thiazoline.

(0030) While the method described in U.S. Patent No. 4,941,994 offers significant improvements over prior art techniques, there is still a desire to expand the capacity of corrosion inhibitors while reducing the amount of phosphorus-containing compounds that can impair the function of various catalysts used to treat crude oil, as well as a desire that such inhibitors can be produced from low-cost or more widely available starting materials.

(0031) Another approach to preventing naphthenic acid corrosion is the use of a chemical agent to form a barrier between crude oil and hydrocarbon processing equipment. This barrier or film prevents corrosive agents from reaching the metal surface and is generally a hydrophobic material.

(0032) Gustavsen et al., Meeting on corrosion NACE 89, text number 449,

April 17-21, 1989, detail the requirements for a good film forming agent. US patent number 5,252,254 discloses a film-forming agent, sulfonated phenol with alkyl substituent, effective against naphthenic acid corrosion.

Petition 870170084741, of 11/03/2017, p. 28/60

13/41 (0033) American patent number 5,182,013 issued to Petersen et al., On January 26, 1993, describes another method of inhibiting crude oil naphthenic acid corrosion which consists of introducing an effective amount of polysulfide into the oil organic. The discovery of US patent number 5,182,013 is hereby incorporated by reference. This is yet another example of a corrosion-inhibiting sulfur species. Sulphide as a corrosion source was detailed above. Although the process is not well understood, it has been determined that although sulfur can be an effective anti-corrosive agent in small amounts, under sufficiently high concentrations it becomes a corrosion agent.

(0034) Phosphorus can form an effective barrier against corrosion without sulfur, but the addition of sulfide agents to the process flow containing phosphorus generates a film composed of both sulfides and phosphates. This results in improved performance as well as less need for phosphorus. This invention concerns the deliberate addition of sulphide agents to the process flow when phosphorus-based materials are used to control corrosion in order to enhance this interaction.

(0035) American patent number 5,314,643 to Edmondson et al. describes a process for inhibiting corrosion caused by naphthenic acid and sulfur compounds during high temperature processing of crude oil through the use of a corrosion inhibitor consisting of a combination of trialkylphosphate and a phosphonate-phenate-alkali metal sulfide - iron, functioning effectively as an inhibitor on the internal metal surfaces of the equipment used in crude oil refining operations.

Petition 870170084741, of 11/03/2017, p. 29/60

14/41 (0036) Organic polysulfides (Babaian-Kibala, US patent number 5,552,085), organic phosphites (Zetlmeisl, US patent number 4,941,994) and phosphate / phosphite esters (Babaian-Kibala, American patent number 5,630,964) are claimed they are effective in the hydrocarbon-rich phase against naphthenic acid corrosion. However, its high oil solubility incurs the risk of lateral contamination of the distillate by phosphorus.

(0037) Phosphoric acid has been used mainly in the aqueous phase to form a complex phosphate / iron film on steel surfaces to inhibit corrosion or other applications (Coslett, British patent 8,667, US patents numbers 3,132,975, 3,460,989 and 1,872,091) . The use of phosphoric acid in non-aqueous, high-temperature environments (petroleum) has also been reported for the purpose of mitigating scale (US patent number 3,145,886).

(0038) There is still a continuing need to develop additional options to mitigate the corrosivity of acidic crude oils at a lower cost. This is especially true in times of low refining margins and high availability of corrosive crude oils from sources such as Europe, China or Africa and India. The present invention addresses that need.

Objectives and advantages of the present invention (0039) Therefore, the objectives and advantages of the present invention are described below.

(0040) An object of the present invention is to provide a chemical composition that will provide a highly effective inhibition of corrosion by naphthenic acid at high temperature, as well as inhibition of sulfur corrosion.

Petition 870170084741, of 11/03/2017, p. 30/60

15/41 (0041) Another objective of the present invention is to provide a composition for inhibiting corrosion, which is quite stable even at high temperature.

(0042) Yet another objective of the present invention is to provide a corrosion inhibiting composition with a very low acid value.

Summary of the Invention (0043) The present invention relates to the hydrocarbon processing field, which causes corrosion on the metal surfaces of the processing units. The invention addresses the technical problem of high temperature naphthenic acid and sulfur corrosion and provides a solution to inhibit these types of corrosion. The 3 combined compositions are formed by 3 mixtures separately, with a mixture obtained by mixing compound A, which is obtained by reacting the highly reactive polyisobutylene (HRPIB) with phosphorus pentasulfide in the presence of a catalytic amount of sulfur with compound B such as trialkyl phosphate and the second mixture obtained by mixing compound A with compound B such as diisodecyl phenyl phosphite type phosphite, and the third mixture obtained by mixing compound A with compound D such as phosphonate, where each one of these 3 mixtures independently provides high corrosion inhibition efficiency in the case of high temperature naphthenic acid and sulfur corrosion. The invention is useful in all hydrocarbon processing units, such as refineries, distillation columns and other petrochemical sectors.

Description of the Invention (0044) It was surprisingly discovered by the inventor of the present invention that a combination of an organophosphoric sulfur compound and any

Petition 870170084741, of 11/03/2017, p. 31/60

16/41 another phosphoric compound such as phosphates, phosphites and phosphonates works quite efficiently in controlling corrosion by naphthenic acid, providing a synergistic effect for the combination of phosphoric compounds. The organophosphoric sulfur compound is made from the reaction of hydrocarbon R1, as well as olefins with phosphorus pentasulfide, in the presence of powdered sulfur. Among the other phosphoric compounds, tributyl phosphate and diisodecyl phenyl phosphite are preferred.

(0045) Preferred olefins have double bonds, where the double bond is present internally or terminally. Details on such a R1 hydrocarbon are given below:

(0046) As previously mentioned, the term "hydrocarbon" as used herein means any one between an alkyl group, an alkenyl group, an alkynyl group, groups which can be linear, branched or cyclic, or an aryl group. The term hydrocarbon also includes these groups, but in which there has been an optionally substitution. If the hydrocarbon is a branched structure with substituents there, then the substitution can be either in the main structure of the hydrocarbon or in the branch; alternatively, the substitutions can be in the main structure of the hydrocarbon and in the branch.

(0047) Preferably R1 is an optionally substituted alkenyl or alkyl group. In one aspect R1 is an optionally substituted alkyl group. In another aspect, R1 is an optionally substituted alkenyl group.

(0048) The term "alkenyl" refers to a branched or straight chain hydrocarbon, which may comprise one or more carbon-carbon double bonds.

Examples of alkenyl group include propylene, butenyl, isobutenyl, pentenyl, 2,2-methylbutenyl, 3-methylbutenyl, hexanyl, heptenyl, octenyl and polymers thereof.

Petition 870170084741, of 11/03/2017, p. 32/60

17/41 (0049) In one aspect R1 is an optionally substituted branched alkenyl or alkyl group. Preferably R1 is a polyisobutenyl (PIB) group.

(0050) Conventional PIBs and so-called “high reactivity” GDPs (see eg EP-B-0565285) are suitable for use in this invention. High reactivity in this context is defined as a GDP where at least 50%, preferably 70% or more, of the olefinic terminal double bonds are of the vinylidene type, for example, the GLISSOPAL compounds available from BASF.

(0051) In one aspect R1 has between 10 and 1000 carbon atoms, preferably between 4 and 200 carbon atoms.

(0052) Trialkylphosphate such as tributyl phosphate will contain a portion of C1-C12 alkyl so that those compounds considered to have the desired efficacy and within the disclosure of the present invention include trimethylphosphate, triethylphosphate, tripropylphosphate, tributylphosphate and tripentylphosphate. Due to its easy commercial availability, tributylphosphate can be considered the preferred compound.

(0053) The most effective amount of the corrosion inhibitor to be used in accordance with the present invention may vary depending on local operating conditions and the specific hydrocarbon being processed. Thus, the temperature and other characteristics of the acid corrosion system can influence the amount of inhibitor or the mixture of inhibitors to be used. Generally, when operating temperatures and / or acid concentrations are higher, a proportionately higher amount of the corrosion inhibitor will be required. It has been found that the concentration of the corrosion inhibitors or mixture of inhibitors added to the crude oil can vary from about 1 ppm to 5000 ppm. It has also been found that it is preferable to add inhibitors to a

Petition 870170084741, of 11/03/2017, p. 33/60

18/41 relatively high initial dosage rate of 2000-3000 ppm and maintain that level for a relatively short period of time until the presence of the inhibitor induces the accumulation of a corrosion protective coating on the metal surfaces.

(0054) When the protective surface is established, the dosage rate required to maintain protection can be reduced to a normal operating range of around 100-1500 ppm without substantial sacrifice of protection.

(0055) The inventor of the present invention carried out an extensive experimentation to verify the effectiveness of corrosion inhibition in the case of corrosion by naphthenic acid, carrying out experiments with different proportions of compound A, that is, polyisobutylene plus phosphorus pentasulfide plus sulfur powder, and compound B, that is, tributyl phosphate in the aforementioned combination of these compounds. Experiments were also carried out using compound A alone and compound B alone separately.

(0056) The inventor of the present invention also carried out extensive experimentation to verify the effectiveness of corrosion inhibition in the case of corrosion by naphthenic acid, carrying out experiments with different proportions of compound A, that is, polyisobutylene plus phosphorus pentasulfide plus sulfur powder , and of compound C, that is, diisodecyl phenyl phosphite, in the aforementioned combination of these compounds. Experiments were also carried out using compound A alone, compound B alone and compound C alone, separately.

(0057) The reacted compound “A” is obtained by reacting the olefins with P 2S5 (phosphorus pentasulfide) in the presence of powdered sulfur. Preferred olefins have double bonds, where the double bond is present internally or terminally.

Petition 870170084741, of 11/03/2017, p. 34/60

19/41 (0058) The example of double-bonded olefins includes betaolefins.

(0059) The example of double-terminally linked olefins includes alphaolefins. These olefins have 5 to 30 carbon atoms. Such olefins are, alternatively, polymeric olefins such as highly reactive polyisobutylene containing over 70% vinylidene double bond and normal polyisobutylene containing vinyl, vinylidene and other groups of chemicals.

(0060) The ratio of P2S5 to olefin is preferably 0.05 to 2 moles of P2S5 to 1 mole of olefins. Powdered sulfur is present in the catalytic amount, that is, powdered sulfur is 0.5% to 5% of the olefin by weight.

(0061) The preferred embodiment of the present invention is described below:

(0062) A measured amount of HRPIB (highly reactive polyisobutylene), phosphorus pentasulfide and sulfur powder are loaded into a clean, four-necked round bottom flask equipped with nitrogen inlet, stirrer and thermometer, thereby forming a mixture reaction.

(0063) The reaction mixture is stirred and heated to a temperature of 160 ° C under a nitrogen gas purge. At this temperature of 160 ° C, the reaction leads to the evolution of hydrogen sulfide gas (H2S). The temperature of the reaction mixture is then maintained between 160 ° C and 180 ° C, for a period of 1 hour to 2 hours. Then the temperature of the mixture is raised to 220 ° C. The reaction mixture is then maintained at this temperature of 220 ° C for 6 hours.

(0064) The resulting reaction mass is then cooled to a temperature of

100 ° C, when the nitrogen gas is purged in the resulting reaction mass to remove the hydrogen sulfide present there. The resulting polyisobutylene phosphorus-sulfur compound is used as a corrosion inhibitor by high naphthenic acid

Petition 870170084741, of 11/03/2017, p. 35/60

20/41 temperature. This compound is used neat or diluted in an appropriate solvent such as xylene, toluene and aromatic solvent like any other suitable solvent to obtain corrosion inhibition by high temperature naphthenic acid. (0065) The present invention is directed to a method of inhibiting corrosion on the metal surfaces of hydrocarbon processing units such as, e.g. crude oil and its fractions containing naphthenic acid. The invention is explained in detail in its simplest form in which the steps of the following method are performed, when it is used to process crude oil in processing units such as the distillation unit. Similar steps can be used in different processing units such as pumping pipes, heat exchangers and other processing units.

(0066) The steps of the method are explained below:

a) heating the hydrocarbon containing naphthenic acid to vaporize a portion of the hydrocarbon:

b) allow the hydrocarbon vapors to rise in a distillation column;

c) condensing a portion of the hydrocarbon vapors passing through the distillation column to produce a distillate;

d) adding to the distillate from 1 to 5000 ppm of the combined compound (A + B) or the combined compound (A + C) of the present invention;

e) allow the distillate containing the combined compound (A + B) or the combined compound (A + C) to contact the entire metal surfaces of the distillation unit to form a protective film on that surface, through which this surface is inhibited against corrosion.

Petition 870170084741, of 11/03/2017, p. 36/60

21/41 (0067) It is advantageous to treat the distillation column, trays, pumping pipes and related equipment to prevent corrosion by naphthenic acid, when condensed vapors from the distilled hydrocarbon fluids come into contact with the equipment at temperatures above 200 ° C, and preferably 400 ° C. The combined compound (A + B) or the combined compound (A + C) as an additive is generally added to the condensed distillate and the condensed distillate is allowed to come into contact with the metal surfaces of the distillation column, casing, trays, pumping pipes and related equipment as the condensed distillate passes through the column and into the distillation flask. The distillate can also be collected as a product. The corrosion inhibitors of the present invention remain in the resulting collected product.

(0068) In commercial practice, the additives of this invention can be added to the return of the distillate to control corrosion in the extraction tray and in the column casing while a second injection can be added to the return of the spray oil immediately below the spray trays. extraction to protect the tower casing and the trays below the distillate extraction tray. It is not so vital when the additive of the invention is added as long as it is added to the distillate that is later returned to the distillation flask, or that comes into contact with the internal metallic surfaces of the distillation column, trays, pumping pipes and related equipment .

(0069) The method of using the polyisobutylene phosphorus-sulfur compound of the present invention to obtain corrosion inhibition by naphthenic acid at high temperature is explained below with the help of examples 1 and 2.

Petition 870170084741, of 11/03/2017, p. 37/60

22/41 (0070) Example 3 shows the use of compound B.

(0071) Example 4 shows the use of the compound compound (A + B) (0072) Example 5 shows the use of compound C.

(0073) Example 6 shows the use of the combined compound (A + C).

(0074) Compound B of the combined compound (A + B) of the present invention is easily obtained commercially.

(0075) The compound C of the combined compound (A + C) of the present invention is easily obtained commercially.

Example 1 (0076) Measured quantities of 68.16 gm of commercially available HRPIB (Highly Reactive Polyisobutylene with molecular weight of approximately 950), 30.31 gm of Phosphorus Pentasulfide and 1.51 gm of Sulfur Powder are loaded into a flask clean round bottom with 4 necks, equipped with N2 inlet, stirrer and thermometer, thereby forming a reaction mixture. This gives: a 1: 1 molar ratio of Phosphorus Pentasulfide to Olefin.

(0077) The reaction mixture was stirred and heated to 160 ° C under a nitrogen gas purge. Purge of N2 gas leads to the removal of hydrogen sulfide gas, which was generated during the reaction. The temperature of the reaction mixture was maintained between 160 ° C and 180 ° C, for a period of 1 hour to 2 hours. Then the temperature of the mixture was raised to 220 ° C and the mixture was kept at that temperature for 6 to 10 hours.

(0078) The resulting reaction mass was then cooled to 100 ° C when the nitrogen gas was purged therein to remove the hydrogen sulfide gas present there. The resulting polyisobutylene-phosphorus-sulfur compound was used as an inhibitor of corrosion by naphthenic acid at high temperature, as well as an inhibitor of corrosion by sulfur. This compound was used pure or distilled in a

Petition 870170084741, of 11/03/2017, p. 38/60

23/41 suitable solvent such as xylene, toluene and aromatic solvent as well as any other suitable solvent to obtain inhibition of corrosion by naphthenic acid at high temperature and corrosion by sulfur.

(0079) The aforementioned synthesis is performed for different molar ratios of 1: 1, 1:05 and 1: 0.25 of HRPIB to Phosphorus Pentasulfide. A similar synthesis was performed using normal polyisobutylene instead of HRPIB, with a 1: 03.5 molar ratio.

Example 2 (0080) High temperature naphthenic acid corrosion test (0081) In this example, various amounts of a formulation at 50% of the composition prepared in accordance with Example 1 were tested for corrosion inhibition efficiency on steel samples in hot oil containing naphthenic acid. A sample immersion test for weight loss was used to evaluate the compound of the invention for its effectiveness in inhibiting naphthenic acid corrosion at a temperature of 290 ° C. Different dosages such as 300, 400 and 600 ppm of the compound of the invention were used, as a 50% active solution.

(0082) The corrosion inhibition test on the steel sample was conducted without using any additives. This test provided the reading of a blank essay.

(0083) The reaction apparatus consisted of a 1 liter round-bottomed flask with four necks equipped with water condenser, N2 bleed tube, thermometer sheath with thermometer and stirring rod. 600 gm (about 750 ml) of paraffin hydrocarbon oil (D-130) was placed in the bottle. The nitrogen gas purge was started at a flow rate of 100 cc / minute and the temperature was raised to 100 ° C, which temperature was maintained for 30 min. A compound of example 1 including Polyisobutylene and Phosphorus Pentasulfide with sulfur powder

Petition 870170084741, of 11/03/2017, p. 39/60

24/41 was added to the reaction mixture. The reaction mixture was stirred for 15 min at 100 ° C. After removing the stirrer, the temperature of the reaction mixture was raised to 290 ° C. A sample of pre-weighed carbon steel for weight loss CS1010 with dimensions of 76 mm x 13 mm x 1.6 mm was immersed. After maintaining this condition for 1 to 1.5 hours, 31 gm of naphthenic acid (commercial grade with an acid value of 230 mg / KOH) was added to the reaction mixture. A sample weighing one gm of the reaction mixture was taken to determine the acidity value, which proved to be approximately 11.7. This condition was maintained for 4 hours. After this procedure, the metal sample was removed, the excess oil was washed away and the excess corrosion product was removed from the metal surface. Then the metal sample was weighed and the corrosion rate was calculated in thousandths per year.

Calculation of the corrosion inhibition efficiency (0084) The method used in the calculation of the Corrosion Inhibition Efficiency is presented below. In this calculation, the corrosion inhibition efficiency provided by the additive compound is calculated by comparing the weight loss due to the additive with the weight loss of the blank test sample (without any additive).

Efficiency of = (weight loss to - (weight loss with additive) X 100 inhibition of the sample without additive) corrosion (weight loss for the blank test sample without additive) (0085)

The calculated quantities are inserted in the Tables in the appropriate columns.

(0086)

The results of the experiments are shown in Table I and II.

Petition 870170084741, of 11/03/2017, p. 40/60

25/41 (0087) The test results of experiments conducted using normal polyisobutylene are provided in Table III.

(0088) corrosion rate in MPY (thousandths per year) is calculated using the formula,

MPY = _________ 534 x weight loss in mg_____________________ (density in gm / cc) x (area in m ² ) x (test time in hours)

Example 3 (0089) Experiments were performed by the inventor of the present invention to test the effectiveness of a commercially available phosphorus compound B, such as tributyl phosphate, in inhibiting naphthenic acid corrosion. Different doses of tributyl phosphate, such as 75, 90 and 100 ppm, were used in the experiments. The results of some of these experiments are shown in Table 5.

Example 4 (0090) Experiments were carried out by the inventor of the present invention to test the synergistic effectiveness of a combination of compounds A and B, where compound A represents highly reactive polyisobutylene plus phosphorus pentasulfide plus powdered sulfur and compound B represents tributyl phosphate (compound B is used as commercially available). Different total dosages of the combination of inhibitor compounds such as 300 ppm and 400 ppm were used in the experiment. Likewise, different proportions of compound A and compound B were used in these experiments. These different percentage proportions of A: B were 67:33, 70:30, 75:25 and 81:19. The results of these experiments are shown in Tables 6 to 8.

Example 5

Petition 870170084741, of 11/03/2017, p. 41/60

26/41 (0091) Using steps of a method similar to that of example 2, the experiments were carried out by the inventor of the present invention to test the effectiveness of another commercially available phosphorus compound C, such as diisodecyl phenyl phosphite, in inhibiting corrosion by naphthenic acid. Different active dosages of Diisodecyl phenyl phosphite, such as 75, 90, 120 and 150 ppm were used in the experiments. The results of these experiments are shown in Table 9.

Example 6 (0092) Using steps of a method similar to that of example 2, the experiments were carried out by the inventor of the present invention to test the synergistic effectiveness of a combination of compounds A and C in inhibiting corrosion by naphthenic acid, where compound A represents the highly reactive polyisobutylene plus phosphorus pentasulfide plus the catalytic amount of powdered sulfur and compound C represents diisodecyl phenyl phosphite (compound C is used as commercially available). Different total active dosages of the combination of inhibitory compounds such as 195, 200, 210, 250 and 300 ppm were used in the experiment. Likewise, these total active dosages included different proportions of active compounds A and C. These different proportions of A: C included 105: 90, 90: 120, 100: 100, 140: 60, 110: 90, 130: 120 and 180: 120. The results of these experiments are shown in Table 10.

Table 1: Corrosion Inhibition Test (with Polyisobutylene molar ratio for

Phosphorus pentasulfide = 1: 1) (Example - 2)

Experiment number Inhibiting compound Dosage in ppm Effective dosage in ppm Lost of Weight in mg Corrosion Index in mg Corrosion inhibition efficiency in% 1 (Trial only - - 89.5 529.89 0

Petition 870170084741, of 11/03/2017, p. 42/60

27/41

White) 2 Composition as in ex. 1 200 100 63.3 371.23 29.27 3 Composition as in ex. 1 300 150 39.6 232.24 55.75 4 Composition as in ex. 1 400 200 15.2 89,114 83.02 5 Composition as in ex. 1 600 300 3.8 12.31 95.75 Composition as in ex. 1 650 325 0.3 1.5 99.67

Table 2: Corrosion Inhibition Test (with Polyisobutylene molar ratio for

Phosphorus pentasulfide = 1: 0.5) (Example - 2)

Experiment number Inhibiting compound Dosage in ppm Effective dosage in ppm Weight Loss in mg Corrosion Index in mg Corrosion inhibition efficiency in% 15 (only Test on White) 87.7 439 0 7 Composition as in ex. 1 500 250 21.5 107.62 75.48

Table 3: Corrosion Inhibition Test (with Polyisobutylene molar ratio for

Phosphorus pentasulfide = 1: 0.25) (Example - 2)

Experiment number Inhibiting compound Dosage in ppm Effective dosage in ppm Weight Loss in mg Corrosion Index in mg Corrosion inhibition efficiency in% 15 (Trial only White) 87.7 439 0 8 Composition as in ex. 1 500 250 50.6 253.3 42.3 9 Composition as in ex. 1 1000 500 14.2 71.08 83.81 10 Composition as in ex. 1 1500 750 2.0 10.1 97.72

Table 4: Corrosion Inhibition Test (with normal Polyisobutylene molar ratio to Phosphorus Pentasulfide = 1: 0.35)

Experiment number Inhibiting compound Dosage in ppm Effective dosage in ppm Weight Loss in mg Corrosion Index in mg Corrosion inhibition efficiency in% 15 (Trial only White) 87.7 439 0 7 Composition as in ex. 1 600 300 40 200.21 54.39

Petition 870170084741, of 11/03/2017, p. 43/60

28/41

Table 5: Corrosion Inhibition Test (inhibitory compound R = Tributyl Phosphate)

Experiment number Inhibiting compound Dosage in ppm Weight Loss in mg Corrosion Index in mg Corrosion inhibition efficiency in% 1 (blank test only) - 89.5 529.89 0 12 Tributyl phosphate (as commercially available) 75 55.5 325.49 37.99 13 Composed as in experiment 12 90 21.95 128.73 75.48 14 Composed as in experiment 12 100 4.35 84.16 83.97

Table 6: Corrosion inhibition test (Inhibiting compound = A + B) (0093) Compound A = 50% Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent (0094 ) Compound B: Tributyl Phosphate (as commercially available) without any solvent (0095) RM = Polyisobutylene Molar Ratio to Phosphorus Pentasulfide

Experiment number R.M. Inhibiting compound Dosage in (ppm) Weight Loss (mg) Corrosion Index in (MPY) Corrosion inhibiting efficiency (%) Compound A Compound B Total dosage A + B 15 - (blank test) - - - 87.70 439 0 16 1 A + B 120 80 200 0 10 100 17 :1 A + B 150 75 225 2.2 11.01 97.49 18 1: 1 A + B 180 60 240 0.7 3.5 99.20

Table 7: Corrosion inhibition test (Inhibiting compound = A + B) (0096) Compound A = 50% Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent (0097 ) Compound B: Tributyl Phosphate (as commercially available) without any solvent (0098) RM = Polyisobutylene Molar Ratio to Phosphorus Pentasulfide

Petition 870170084741, of 11/03/2017, p. 44/60

29/41

Experiment number .M. Inhibiting compound Dosage in (ppm) Lost of Weight (mg) Corrosion Index in (MPY) Corrosion inhibiting efficiency (%) Compound A Compound B Total dosage A + B 1 - (blank test only) - - - 89.5 529.89 0 19 :1 A + B 200 100 300 2.73 16.01 96.95 20 :1 A + B 210 90 300 2.90 17.00 96.76 21 :1 A + B 225 75 300 5.30 31.08 94.08 22 :1 A + B 325 75 400 4.70 27.56 94.75

Table 8: Corrosion inhibition test (Inhibiting compound = A + B) (0099) Compound A = 50% Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent (00100 ) Compound B: Tributyl Phosphate (as commercially available) without any solvent (00101) RM = Molar Ratio of Polyisobutylene to Phosphorus Pentasulfide

Experiment number .M. Inhibiting compound Dosage in (ppm) Weight Loss (mg) Corrosion Index (MPY) Corrosion inhibiting efficiency (%) Compound A Compound B Total dosage A + B 15 (blank test only) 87.7 39 0 23 : 0.5 A + B 300 75 375 1.8 , 01 97.95 24 : 0.5 A + B 330 60 390 5.2 6.03 94.07 25 : 0.5 + B 25 5 00 9.4 97.21 5.07

Table 9: Corrosion inhibition test (Inhibiting compound C = Diisodecyl Phenyl

Phosphite as commercially available without any solvent)

Experiment number Inhibiting compound Dosage in ppm Weight Loss mg Index of Corrosion in mg Corrosion inhibition efficiency in% 15 (blank test only) - 7.70 439 0 26 Phenyl diisodecyl phosphite without any solvent 75 3.90 369.90 15.74 27 Composed as in experiment 26 90 8.5 292.81 33.30 28 Composed as in experiment 26 120 1.0 105.11 76.05 29 Composed as in experiment 26 150 60 8.01 98.18

Petition 870170084741, of 11/03/2017, p. 45/60

30/41

Table 10: Corrosion inhibition test (Inhibiting compound = A + C) (00102) Compound A = 50% Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent (00103 ) Compound C = Diisodecyl phenyl phosphite as commercially available without any solvent

Experiment number .M. Inhibiting compound Dosage in (ppm) Lost of Weight (mg) Corrosion Index in (MPY) Corrosion inhibiting efficiency (%) Compound A Compound B Total dosage A + C 15 - (blank test) - - - 87.70 439 0 30 :1 A + C 210 90 300 4.9 24.53 94.41 31 :1 A + C 180 120 300 0.7 3.5 99.20 32 :1 Ç 200 100 300 0.3 1.5 99.66 33 :1 A + C 280 60 340 0.4 2.0 99.54 34 :1 A + C 220 90 310 0.1 0.5 99.89 35 : 0.5 A + C 260 120 380 1.5 7.51 98.29 36 : 0.5 A + C 360 120 480 3.4 17.02 96.12

Table 11: Corrosion inhibition test (Inhibiting compound = A + B) (00104) Compound A = 50% Normal Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent ( 00105) Compound B: Tributyl Phosphate (as commercially available) without any solvent (00106) RM = Polyisobutylene Molar Ratio to Phosphorus Pentasulfide

Experiment number .M. Inhibiting compound Dosage in (ppm) Weight Loss (mg) Corrosion Index in (MPY) Corrosion inhibiting efficiency (%) Compound A Compound B Total dosage A + B 15 (blank test only) 87.7 39 0 37 : 0.35 A + B 320 90 410 1.3 6.5 98.52

Table 12: Corrosion inhibition test (Inhibiting compound = A + C)

Petition 870170084741, of 11/03/2017, p. 46/60

31/41 (00107) Compound A = 50% Normal Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (according to example 1) and 50% solvent (00108) Compound C = Diisodecil phenyl phosphite as commercially available without any solvent

Experiment number .M. Inhibiting compound Dosage in (ppm) Lost of Weight (mg) Corrosion Index in (MPY) Corrosion inhibiting efficiency (%) Compound THE Compound B Total dosage A + C 15 (blank test only) 87.70 439 0 38 : 0.3 5 A + C 360 120 480 24.2 121 72.41 (00109) Discussion of the results presented the ta beautiful

(00110) The detailed discussion presented below with respect to the results shown in Tables 1 to 12 for the experiments described in Examples 1 to 6 explains the effectiveness of the additive inhibiting compounds of the present invention in inhibiting corrosion by naphthenic acid at high temperature or inhibition of sulfur corrosion.

(00111) additive inhibiting compound of the present invention, which is quite effective in inhibiting naphthenic acid corrosion at high temperature, consists of a mixture of compound A with one of the two compounds B and C, where (00112) A = 50 % of the reaction product of Polyisobutylene plus Phosphorus Pentasulfide + catalytic amount of Sulfur powder (as in example 1) and 50% of solvent.

(00113) B = Tributyl Phosphate (as commercially available), without any solvent.

Petition 870170084741, of 11/03/2017, p. 47/60

32/41 (00114) C = Diisodecyl Phenyl Phosphite (as commercially available), without any solvent.

(00115) The results presented in Tables 1 to 12 show separately the effectiveness of each of the three compounds A, B and C and also separately the effectiveness of each of the two mixtures (A + B) and (A + C). The detailed discussion presented below shows a greatly improved efficacy in inhibiting naphthenic acid corrosion at high temperature by each of the two mixtures (A + B) and (A + C), compared to the effectiveness of each of the compounds A, B and C separately. The greatly improved effectiveness of the inhibitor compound of the present invention, that is, one of the mixtures (A + B) or (A + C), is observed from the high corrosion inhibition efficiency, even with the reduction in the total dosage of the components active.

(00116) Tables 1 to 3 show the results of the efficacy of compound A, for three different molar ratios of the Highly Reactive Polyisobutylene for Phosphorus Pentasulfide, such as 1: 1, 1:05 and 1: 0.25. Table 4 shows the results of the effectiveness of compound A with a molar ratio of Normal Polyisobutylene to Phosphorus Pentasulfide of 1: 0.35.

(00117) Table 5 shows the results of the efficacy of compound B, i.e., Tributyl Phosphate, as commercially available, without any solvent.

(00118) Table 9 shows the results of the effectiveness of compound C, that is, Diisodecyl Phenyl Phosphite, as commercially available, without any solvent.

(00119) The three tables 6 to 8 show the effectiveness of the additive compound consisting of the mixture (A + B) of the present invention, with two molar ratios: 1: 1 and

1: 0.5 of two components of A, that is, the Highly Reactive Polyisobutylene and the

Phosphorus pentasulfide.

Petition 870170084741, of 11/03/2017, p. 48/60

33/41 (00120) Table 10 shows the effectiveness of the additive compound consisting of the mixture (A + C) of the present invention, with a 1: 1 molar ratio of Highly Reactive Phosphorus Phosphide Sulfide.

(00121) Discussion of the rather high effectiveness of the mixture (A + B), that is, the additive compound of the present invention, in inhibiting corrosion by naphthenic acid

a) Referring to Table 1, an effective active dosage of compound A (molar ratio 1: 1) of 300 ppm and 325 ppm was necessary to obtain a corrosion inhibition efficiency of 95.75% and 99.67% , respectively.

b) Referring to Table 2, an effective active dosage of compound A (molar ratio 1: 0.5) of 250 ppm was necessary to obtain a corrosion inhibition efficiency of 75.48%.

c) Referring to Table 3, an effective active dosage of compound A (molar ratio 1: 0.25) of 500 ppm and 750 ppm was necessary to obtain a corrosion inhibition efficiency of 83.81% and 97, 72%, respectively.

d) Referring to Table 4, an effective active dosage of compound A, with normal polyisobutylene (molar ratio 1: 0.35), of 300 ppm resulted in a corrosion inhibition efficiency of only 54.39%.

e) Referring to Table 5, an effective active dosage of compound B of 100 ppm resulted in a corrosion inhibition efficiency of only 83.97%.

f) In contrast, referring to Table 6, a total effective active dosage of the mixture (A + B) of 150 ppm (75 ppm of A and 75 ppm of B) and 150 ppm (90% of A and 60 ppm of B) resulted in a corrosion inhibition efficiency of 97.49% and 99.20%, respectively.

(00122) This clearly demonstrates the inventiveness of the sample (A + B) of the present invention, since a high corrosion inhibition efficiency of

Petition 870170084741, of 11/03/2017, p. 49/60

34/41 about 97% and 99% is acquired with very low total effective active dosages of the mixture (A + B), that is, 150 ppm. This will result in tremendous savings due to the very low dosages of the mixture.

(00123) Discussion of the rather high effectiveness of the mixture (A + C), that is, the additive compound of the present invention, in inhibiting corrosion by naphthenic acid (00124) Referring to Table 9, an effective active dosage of the compound C, of 120 ppm and 150 ppm, resulted in a corrosion inhibition efficiency of 76.05% and 98.18%.

(00125) In contrast to the results presented in Tables 1 to 9, as discussed above, the total effective active dosages of the mixture (A + C) of the present invention in the value of 200 ppm (140 ppm A and 60 ppm C) resulted in a corrosion inhibition efficiency of 99.54%. This leads to substantial savings when it is noted that compound C is quite expensive compared to compound A.

(00126) Thus, it can be seen from the previous discussion that the additive compounds formed by two separate mixtures (compound A + compound B) and (compound A + compound C) of the present invention, used to inhibit corrosion, have the important distinctive feature below compared to the prior art.

(00127) inventor of the present invention, after extensive experimentation, found surprisingly that the two additive combined compounds, each used by the inventor as an additive, that is, the two combined compounds formed by two separate mixtures (compound A + compound B) and (compound A + compound C), are both effective in inhibiting corrosion by high temperature, as shown by the experimental results in Tables 1 to 11.

Petition 870170084741, of 11/03/2017, p. 50/60

35/41 (00128) The prior art does not teach or suggest the use of the mixture (A + B) or (A + C) in inhibiting corrosion by naphthenic acid or in inhibiting corrosion by sulfur or in any inhibition of corrosion in general .

(00129) In view of the details provided in the previous description of the present invention, it will be clear to a person skilled in the art that the present invention basically includes the following items:

Item 1 (00130) A high temperature naphthenic acid corrosion inhibiting composition consisting of a chemical mixture with a corrosion inhibiting amount of a compound A with olefin, phosphorus and sulfur with a corrosion inhibiting amount of any organophosphoric compound selected from the group consisting of compound B, compound C and compound D; where such olefin, phosphorus and sulfur compound A is produced by reacting such olefin with phosphorus pentasulfide in the presence of a catalytic amount of sulfur, capable of forming a molar ratio reaction mixture of such olefin to such phosphorus pentasulfide being between 1: 0.05 and 1: 1.5, preferably 1: 1, where such compound B is a phosphate ester of the formula

O

II ·

R1O-P-OR ₂

I or ₃ (00131) Where R1 and R2 are each independently selected from the group consisting of hydrogen and portions with one to thirty carbon atoms, and R3 is a portion that contains one to thirty carbon items; and where said compound C is an aryl containing a phosphite compound that excludes nitrogen and has a structure selected from the group consisting of

Petition 870170084741, of 11/03/2017, p. 51/60

36/41

(00132) Where Ri, R2 and R3 are C6 to C12 alkyl or aryl and at least one group R is an aryl radical; and where said compound D is a phosphonate.

Item 2 (00133) A composition, as described in item 1, where such an olefin is polyisobutylene, which is highly reactive or normal.

Item 3 (00134) A composition, as described in items 1 and 2, in which said compound of olefin, phosphorus and sulfur is reached by stirring and heating said reaction mixture of item 1 to 160 ° C under purging of nitrogen gas , maintaining said reaction mixture between 160 ° C and 180 ° C for a period of 1 hour to 2 hours, raising the temperature of said reaction mixture from 185 ° C to 250 ° C, preferably from 190 ° C to 230 ° C, more preferably from 210 ° C to 225 ° C, and maintaining said reaction mixture with the elevated temperature from 1 hour to 24 hours, preferably for 6 to 10 hours, cooling the reaction mass to 100 ° C and purging the nitrogen gas in the reaction flask to remove hydrogen sulfide gas, thereby resulting in said composition.

Item 4 (00135) A composition according to item 1, 2 or 3 where said olefin is an optionally substituted hydrocarbon group.

Petition 870170084741, of 11/03/2017, p. 52/60

37/41

Item 5 (00136) A composition according to any of the previous items where said olefin is an optionally substituted alkenyl or alkyl group.

Item 6 (00137) A composition according to any of the previous items where said olefin is an optionally substituted alkenyl or branched alkyl group.

Item 7 (00138) A composition according to any of the preceding items where said olefin has between 10 and 1000 carbon atoms.

Item 8 (00139) A composition according to any of the preceding items where said olefin has between 4 and 200 carbon atoms.

Item 9 (00140) A composition according to any of the preceding items where said olefin has a molecular weight between 200 and 10,000.

Item 10 (00141) A composition according to any of the preceding items where said olefin has a molecular weight of approximately 200 to approximately 1300.

Item 11 (00142) A composition, consisting of such a mixture of compound A and compound B of items 1 and 14, where said phosphate ester B is selected from the group consisting of phosphate, diphosphate, triphosphate and tributyl phosphate, preferably tributyl phosphate.

Petition 870170084741, of 11/03/2017, p. 53/60

38/41

Item 12 (00143) A composition as described in item 1, wherein said aryl containing the phosphite C compound is selected from the group consisting of triphenyl phosphite, diphenyl phosphite, diphenyl isodecyl phosphite, diphenyl isooctyl phosphite, diisodecyl phenyl phosphite and mixtures thereof, preferably diisodecyl phenyl phosphite. Item 13 (00144) A composition as described in item 12, where said tributyl phosphate is of a type that is commercially available.

Item 14 (00145) A composition as described in item 12, where said diisodecyl phenyl phosphite is of a type that is commercially available.

Item 15 (00146) A composition as described in items 1, 11 and 13, where the amount of said mixture of compound A and compound B, which must be added to the crude oil to inhibit corrosion by naphthenic acid at high temperature, is about 1 ppm to about 300 ppm.

Item 16 (00147) A composition as described in item 15, where the ratio of compound A to compound B, by weight, is about 0.1: 2 to about 2: 0.1. Item 17 (00148) A composition as described in items 1, 12 and 14, where the amount of said mixture of compound A and compound C, which must be added to the crude oil to inhibit naphthenic acid corrosion at high temperature, is about 1 ppm to about 5000 ppm, preferably about 1 ppm to about 300 ppm.

Petition 870170084741, of 11/03/2017, p. 54/60

39/41

Item 18 (00149) A composition, as described in item 17, where the ratio of compound A to compound C, by weight, is about 0.1: 2 to about 2: 0.1. Item 19 (00150) A composition, as described in item 1, where the amount of the mixture of compound A and compound D, which must be added to the crude oil to inhibit corrosion by naphthenic acid at high temperature, is about 1 ppm to about 5000 ppm, preferably from about 1 ppm to 300 ppm.

Item 20 (00151) A composition, as described in item 19, where the ratio of compound A to compound D, by weight, is about 0.1: 2 to about 2: 0.1. Item 21 (00152) A process for inhibiting corrosion by naphthenic acid at high temperature and / or inhibiting corrosion by sulfur at high temperature of metal surfaces of any of the hydrocarbon processing units, with said processing units consisting of columns distillers, degassers, pumping pipes and related equipment, using the combined inhibitor compound as any mixture from 3 mixtures, such as a mixture of the two compounds A and B of items 1, 2, 11 and 13 or a mixture of two compounds A and C of items 1, 2, 12 and 14 and a mixture of the two compounds A and D of items 1, 2, 19 and 20, comprising the steps of:

a) heating the hydrocarbon containing naphthenic acid and / or sulfur compounds to vaporize a portion of said hydrocarbon;

Petition 870170084741, of 11/03/2017, p. 55/60

40/41

b) condensing a portion of the hydrocarbon vapors, passing through said hydrocarbon processing unit to produce a condensed distillate;

c) adding said distillate, before said condensed distillate is returned to said hydrocarbon processing unit or collected as a product from about 1 ppm to about 5000 ppm, preferably from about 1 ppm to 300 ppm of said combined compound inhibitor such as any mixture from 3 mixtures, such as said mixture of the two compounds A and B of items 1, 2, 11 and 13, or said mixture of the two compounds A and C of items 1, 2, 12 and 14 and said mixture of the two compounds A and D of items 1,2, 19 and 20, where the weight ratio from A to B is from about 0.1: 2 to about 2: 0.1 and A to C ratio is about 0.1: 2 to about 2: 0.1 and the weight ratio from A to D is about 0.1: 2 to about 2: 0.1;

d) allowing said condensed distillate containing said combined inhibitor compound like any mixture from 3 mixtures, such as said mixture of the two compounds A and B of items 1, 2, 11 and 13 or said mixture of the two compounds A and C of items 1, 2, 12 and 14 and said mixture of the two compounds A and D of items 1, 2, 19 and 20, to make contact with said metal surfaces of said hydrocarbon processing unit at in order to form a protective film on said surfaces whereby each surface is inhibited against corrosion; and

e) allowing said condensed distillate to return to said hydrocarbon processing unit or to be harvested as said product.

(00153) Although the invention has been described with reference to certain preferred embodiments, the invention is not intended to be limited to those embodiments.

Petition 870170084741, of 11/03/2017, p. 56/60

41/41

Changes to the preferred embodiments described are possible without departing from the spirit of the invention. However, the process and composition described above are intended to be illustrative only and the innovative features of the invention can be incorporated into other forms without departing from the scope of the invention.

Claims (13)

1. “NAFTENIC ACID CORROSION INHIBITOR COMPOSITION”, comprising a chemical mixture of: i) an corrosion inhibiting amount of an A, olefin, phosphorus and sulfur compound; ii) with a corrosion inhibiting amount of any organophosphoric compound selected from the group consisting of: a) compound B; b) compound C; and c) compound D; characterized in that said olefin, phosphorus and sulfur compound A is produced by reacting said olefin with phosphorus pentasulfide in the presence of a catalytic amount of sulfur, where the molar ratio of said olefin to said phosphorus pentasulfide is selected from a group comprising the molar ratio ranging from 1: 0.05 to 1: 1.5, preferably being 1: 1; and where said olefin is polyisobutylene; where compound B is a phosphate ester of the formula O II RiO-P — OR ₂ ORg where R1 and R2 are each independently selected from the group consisting of hydrogen and portions of one to thirty carbon atoms and R3 being a portion of one to thirty carbon atoms; and where said compound C is an aryl containing phosphite compound and excluding nitrogen, having a structure selected from the group consisting of Petition 870190005526, of 01/17/2019, p. 5/9 2/5 where Ri, R2 and R3 are C6 to C12 alkyl or aryl and at least one group R is an aryl radical; and where said compound D is a phosphonate; where said corrosion inhibiting amount of said mixture of said compound A and any of the organophosphate compounds selected from the group consisting of said compound B, said compound C and said compound D are between 1 ppm to 5000 ppm. 2. "COMPOSITION" according to claim 1, characterized in that the polyisobutylene is highly reactive containing at least 50% or more of double vinylidene bond, or said polyisobutylene is a normal polyisobutylene containing vinyl, vinylidene. 3. "COMPOSITION" according to claim 1, characterized in that the compound A of olefin, phosphorus and sulfur is obtained by: a) stirring and heating a mixture comprising said olefin, said phosphorus pentasulfide and said sulfur to 160 ° C under purging of nitrogen gas; b) keeping said mixture between 160 ° C and 180 ° C for a period of 1 hour to 2 hours; c) raising the temperature of said mixture to a temperature selected from the group comprising a temperature ranging from 185 ° C to 250 ° C, from 190 ° C to 230 ° C and from 210 ° C to 225 ° C; and Petition 870190005526, of 01/17/2019, p. 6/9 3/5 d) maintaining said mixture with said elevated temperature for a period selected from the group comprising a period ranging from 1 to 24 hours and from 6 to 10 hours; e) cool said mixture to 100 ° C and purge nitrogen gas into the reaction vessel to expel hydrogen sulfide gas, f) thereby resulting in said olefin phosphorus sulfur compound A. 4. "COMPOSITION" according to any one of the preceding claims, characterized in that the olefin has between 10 and 1000 carbon atoms. 5. "COMPOSITION" according to any one of the preceding claims, characterized by the olefin having between 10 and 200 carbon atoms. 6. "COMPOSITION" according to any one of the preceding claims, characterized in that the olefin has a molecular weight selected from the group comprising a molecular weight ranging from 200 to 10,000 and from 200 to 1300. 7. "COMPOSITION" according to claim 1, comprising said mixture of compound A and compound B, characterized in that said phosphate ester B is selected from the group consisting of phosphate, diphosphate, triphosphate and tributyl phosphate. 8. "COMPOSITION" according to claim 1, characterized in that the aryl-containing phosphite compound C is selected from the group consisting of triphenyl phosphite, diphenyl phosphite, diphenyl isodecyl phosphite, isooctyl diphenyl phosphite, diisodecyl phenyl phosphite and their mixtures. 9. "COMPOSITION" according to claim 1, characterized in that it further comprises tributyl phosphate in which said tributyl phosphate is of a type that is commercially available. 10. "COMPOSITION", according to claim 8, characterized by the Petition 870190005526, of 01/17/2019, p. 7/9 The said phenyl diisodecyl phosphite is of a type that is commercially available. 11. "COMPOSITION" according to any one of the preceding claims, characterized by the amount of said mixture of said compound A and any of the compounds selected from the group consisting of said compound B, said compound C, and said compound D , which must be added to the crude oil to inhibit naphthenic acid corrosion range from 1 ppm to 300 ppm. 12. "COMPOSITION" according to claim 1, characterized by said compound A for any of the compounds selected from the group consisting of said compound B, said compound C, and said compound D, by weight, varies between 0.1: 2 and 2: 0.1. 13. "PROCESS", for the inhibition of naphthenic acid corrosion and / or the sulfur corrosion inhibition of metal surfaces of any of the hydrocarbons, processing units, with said processing units comprising distillation columns, strippers, trays, pumping around pipes and related equipment, using an inhibitory composition comprising a mixture of said olefin phosphorus sulfur compound A and said organophosphate compound selected from the group consisting of said compound B, said compound C and said compound D according to any one of claims 1 to 12, characterized in that it comprises the steps of: The. Heating the hydrocarbon containing naphthenic acid and / or sulfur compounds, to vaporize a portion of said hydrocarbon; B. Condense a portion of the hydrocarbon vapors, passing through the Petition 870190005526, of 01/17/2019, p. 8/9 5/5 said hydrocarbon processing unit, to produce a condensed distillate; ç. Add to said distillate, before said condensate distillate is returned to said hydrocarbon processing unit or collected as a product, an amount selected from the group comprising an amount ranging from 1 ppm to 5000 ppm and 1 ppm to 300 ppm of said inhibitory composition, wherein the weight ratio of said compound A to said organophosphate compound selected from the group consisting of said compound B, said compound C and said compound D varies between 0.1: 2 and 2: 0.1 ; d. Allowing said condensate distillate containing said inhibitor composition to contact said metal surfaces of said hydrocarbon processing unit, to form a protective film on said surfaces, whereby each surface is inhibited against corrosion; and and. Allow said condensate distillate to return to said hydrocarbon processing unit, or to be collected as said product.